Number of Malpighian tubules present in a cockroach is:

Which of the following is absent in the mouthparts of a housefly?

Match the column-$I$ with column-$II$ and select the correct option (in cockroach):-

Column-$I$	Column-$II$
$A$. Mushroom gland	$P$. $6^{th}$ segment
$B$. Testis	$Q$. $2^{nd}-6^{th}$ segments
$C$. Spermatheca	$R$. $4^{th}-6^{th}$ segments
$D$. Ovaries	$S$. $6^{th}-7^{th}$ segments

In a cockroach,the grinding of food takes place in the ........?

The heart of a cockroach is ...... .

Which of the following statement$(s)$ is/are correct about the nervous system of a cockroach?
$(i)$ It consists of a series of fused segmentally arranged ganglia joined by paired longitudinal connectives on the ventral side.
$(ii)$ There are six ganglia lie in the thorax,and three in the abdomen.
$(iii)$ The sense organs are antennae,eyes,maxillary palps,labial palps,and anal cerci,etc.
$(iv)$ Each eye consists of about $5000$ hexagonal ommatidia.